Understanding how to use the M/S technique

The middle and side stereo coding, or just M/S, is a technique that transforms the left and right channels into a middle channel and a side channel. The middle channel is the sum of the left and right channels and the side channel is the difference between the left and right channels.

The biggest advantage of the M/S technique on the recording is flexibility since stereo imaging is directly dependent on the amount of signal coming to the side channels, raising or lowering the ratio of middle to side channels will create a wider or narrower stereo field.

On a standard stereo audio file the middle signal will content about 90% of the audio information, and using the middle and side stereo coding it is possible to control the left and the right channels of a stereo file without changing the stereo,  (left and right) balance, so that is the main reason the mastering engineers uses the M/S coding technique continuously on post-production.

Be aware that the Acustica Audio products automatically encode the input signal from stereo to M/S, and the output signal from M/S to stereo. In this way, there is no need to use additional third-party M/S encoders or decoders in the signal chain, however, the input signal should be a real stereo signal.